Electrical testing apparatus



y 1 w. A. FROECKMAN ELECTRICAL TESTING APPARATUS Filed Dec. 12, 1930 2Sheets-Shet l y 30, 1933- w. A. FROECKMAN 1,912,185

ELECTRICAL TESTING APPARATUS Filed Dec. 12, 1930 2 Sheets-Sheet 2 a? /aaUNITED STATES PATIENT FF WILLIAM A. rironcnivmiv, or sr. Louis,MISSOURI" ELECTRICAL TESTING APPAR ATUS Application filed December 12,1930. Serial No. 501,829.

This invention relates to electrical testing apparatus, and with regardto certain more specific features, to a device for testing electricalcircuits, especially wiring circuits of buildings and the like.

Among the several tion may be noted the trical testing device W objectsof the invenprovision of an elechich is adapted to be used in testingelectrical sockets or the like in a building wiring circuit or the like;the provision of a device of the class described which may be used inmaking various tests for determining the nature of an error which hasbeen made in a wiring circuit; the pro vision of a testing device of theclass described which uses a given number of electrical cells and lampsi n various circuit combinations to eflect a variety of tests; theprovision of a device of the class described which may conveniently bemade in the form of a flashlight of simple and rugged form and which hasno continuously moving parts; and the provision of an electrical testingdevice of this class which may be economically fabricated. Other objectswill be in part obvious and in part pointed out hereinafter.

i The invention accordingly comprises the elements and combinations ofelements, features of construction,

and arrangements of parts which will be exemplified in the, structurehereinafter described, and the-scope of the application of which will beindicated in the following claims.

111 the accompanyin or drawings, in which is illustrated one of variouspossible embodiments of the invention,

Fig. 1 is a longitudinal section of a portion of my testing devicevwhich portion is conveniently made to include only one flashlight cell;

Fig. 2 is a schemat the parts of Fig. 1;

Fig. 3 is a side elevation of a flashlight and ic circuit diagram ofconnections comprising a current supply;

Fig. 4 is a wiring diagram illustrating uses of theinvention, inclusiveof a test for a short-circuit;

Fig. 5 is a wiring diagram showing a test on a circuit having cor ets;

rectly connected sock- Fig. 6 is a wiring diagram'showing ate'st on acircuit having incorrectly:connectod. sockets; and,

Fig. 7 is a wiring diagram showing a test on a circuit having a socketwith both termie nals of said socket connected to the same lead.

Similar reference characters indicate corresponding parts throughout theseveral views of the drawings. I

Referring now more particularly to Fig. 1, there is illustrated atnumeral 1 a flashlight casing provided with caps 3 and 5. Screw cap3'holds in assembled relation the lens 7 and the socket reflector 9, anabutment 11 being provided against which the reflector 9 may rest. Abulb 13 is screw-ed into the socket reflector 9 and the central contactof the bulb makes contact with the zinc casing 15 of the dry batterycell or electromotive means 17. An insulating sleeve 19 surrounds thecell 17 and insulates the cell from the casing 1. f v

The cap 5 is provided with a socket 21 at its central portion forreceiving a terminal extension 23. This terminal extension 23 preferablyshould be all or in part flexible so that the device may convenientlybeused in testing sockets and like apparatus which are'not fullyexposed, such as shaded lighting fixtures. The casing of the extensionmayconveniently comprise a flexible conduit25 which is adapted to'bescrewed at one end 27 into the socket 21 and which is provided at theother end with a terminal disk portion 29 5 which is small enough to fitwithin an electric light socket. i

Mounted on the terminal 29 is; a second terminal 31 adapted to contactwith the inner or central terminal of an electric light socket.

switching member 43 adapted to make contact with the protruding carbonelement 37.

This spring member 43 protrudes slightly from the casing 1 so that itmay be moved to break its contact withthe carbon element 37 and makecontact with the portion at point 45, as illustrated by the dotted linesin Fig. 1. It will be noted that the insulating member 19 is providedwith an opening 47 of such a size that in either position, the springmember 43 does not contact with the casing 1; and that in its normalposition (contacting with the carbon element 37) the spring member doesnot contact with the member 35.

The portion 35 is insulated from the screw cap 5 by means of a sleeve 49which also is adapted to aid in properly spacing the component parts ofthe assembly. This sleeve 49 is insulated from the conduit 25. and thescrew cap 5.

may conveniently comprise a part of the sleeve 19.

The center terminal 31 is connected to the switch member-43 by means ofa wire 51 which The circuit through the device is as fol lows, startingwith the central terminal 31 and considering that the switch 43 is incontact with the carbon element 37, the central contact 31 beingpositive because the wire 51 connects the contacting switch member 47with the terminal 31: the negative zlnc casing 15 of the cell 17,contacts with the central contact 53 of the bulb 13. The outer contact55 of the bulb 13 is in contact with the reflector 9 which is incontactwith the outer terminal disk 29 by means of the casing 1, cap 5, and theconduit 25. The terminal 29 is. therefore. negative.

g This circuit is shown schematically in Fig. 2. It is clear that thereis provided when the switch is in its normal position (full lines) aseries connection of the cell 17 and the bulb 13 with the contactterminals 29 and 31,,said terminals 29 and 31; being at the polar itiesindicated. It is also clear that'if the switch 43 be moved so that itcontacts with the zinc part 35 at the point 45 (see also Fig. 1), thebulb 13 only is in series with the terminals 29 and. 31 and that neitherof these terminals assumes a polarity from the cell 17 (Fig. 2).

" In the'p referred method of using this testing device, I connect oneor more (preferably several) cells to the wiring system to be tested, soas'to provide a direct current voltage at each of the sockets or thelike to be tested. Assuming that a three-wire-grounded-neutral wiringsystem is to be tested, the device F shown in Fig. 3 may be used asshown in Fig. 4 to conveniently supply the direct current voltage fortesting. The device F comprises a flashlight 57 provided at its rearscrew cap 59 with abayonet plug and socket arrangement 61 connecting 3lead-wires 63,

tive element.

' Test for short in Fig. 4, thentesting device shown in F igs.

1 and 2 is used as follows:

Soclcet test (correctly connected,-

'4 and 5) In Fig. 4, the sockets 83 are shown connected to the wiringsystem in the proper manner, that is, their shells 85 are connected toground. 7

Fig. 5 shows schematically the wiring diagram when the testing device ofFigs. 1 and 2 is inserted in a socket which is properly connected. It isclear that such a connection placesthe 4% volt battery 71 and the cell17 in series aiding so that the bulb 13 burns with full brillianceinduced by the combined Voltages of the cells 17 and 71. Hence bothof-the bulbs 13 and 69 are inseries with a 6 volt source, the voltage ofcell 17 being 1 The full brilliance of the bulb 13 is the signal thatthe socket is correctly wired.

Sockets incorrectly connected war reverse polarity 6) If a socket beconnected sothat the inner terminal 87 is grounded instead of the shell85, the connections for a test are shown in Fig. 6. hen thetestingdeviceis inserted in the socket, the bulb 13 will light to only a dull red.This condition obtains because the 4 volt battery 71 is in seriesopposition with the 1 volt battery 17 and the'two bulbs 69 and 13 are inseries with these bucking voltages. the net volta e applied to the twobulbs being three volts.

Boti'z, terminals of soclcet connected to same 13 burns with the voltageof the cell 17 (1 volts) applied thereto. To clearly establish this testand distinguish between the low brilliance (Fig. 7) and a fullbrilliance (Fig. 5) or the brilliance of 6 the switch arm 43 is pressedso that it is shifted to the dotted line position shown. It the socketis a twotimer (Fig. 7) the bulb 13 will not light when the switch isheld in the dotted-line position for it is clear (Fig. 7 that the cell17 is removed from the circuit and by-passed, the circuit beingreclosed. In Figs. 5 and 6, however, it will be noted that when theswitch 43 is shifted to the dotted line position, that both the bulbs 13and 69 are in series with the battery 71 and a light therefore obtainsfor the bulb 13 which is below the respective brilliances for theconnections referred to when the switch 43 is not shifted.

The lens 7 is frosted in order to aid in distinguishing the differentdegrees of brilliance of the bulb 13.

The above tests are given as exemplary and others will suggestthemselves. It will be seen that in effect the lamps 13 and 69 compriseresistances Which cooperate with the respective batteries to providevariations in brilliance under difl'erent arrangements, depending uponthe type of defect, and at the same time, their lighting eliect is thesignal whereby the defects are identified.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes could be made in carrying out the aboveconstructionswithout departing from the scope of the invention, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

I claim:

1. In a tester for circuits having possibly defectively arrangedterminals, means for applying a voltage to such a circuit, another meansfor applying a voltage to said circuit from said defective terminals,said last-named means comprising a battery and a signal adapted to beplaced in a .series across said terminals and means for by-passing saidbattery.

2. In a tester for circuits having possibly defectively arrangedterminals, means for applying a voltage to a circuit, another means forapplying another voltage to said circuit from said defective terminals,said lastnamed means comprising a battery and a sig nal adapted to beplaced in a series across said terminals and means for by-passing saidbattery, whereby at least three variations of resistance and voltage maybe eiiected so as to provide at least three variations in intensity ofsaid signal under different circuit conditions.

3. In a tester for circuits having possibly defectively arrangedterminals, means for circuit from .said defective terminals, said 1last-named means comprising a battery and a signal adapted to be placedin a series across said terminal, means for by-passing said battery,whereby at least three variations may be efi'ected so as to provide atleast three variations of intensity of said signal under difierentcircuit conditions and a signal adapted to be energized by saidfirst-named source of voltage, whereby the existence of a circuit forsaid first-named voltage may-be determined.

4. In apparatus of the class described, circuit energizing meanscomprising a battery and a signal in series, means for attaching saidcircuit energizing means to a circuit, a second energizing meanscomprising a battery and signaling means in series therewith, saidlast-named battery operating with the circuit to be tested in bucking oraiding arrangement according to the conditions of said circuit, andmeans for by-passing said last-named battery without permanentlybreaking the circuit.

5. In apparatus of the class described, circuit energizing meanscomprising a battery and signal in series, means for attaching saidcircuit energizing means to a circuit, a second energizing meanscomprising a battery and signal in series therewith, said second-namedbattery operating with the circuit to be tested in bucking or aidingarrangement and means for throwing the second-named battery out ofcircuit, said second-named battery bein of a diiierent voltage than saidfirst-named battery.

(5. In apparatus of the class described, circuit energizing meanscomprising a battery and signal in series, means for attaching saidcircuit energizing means to a circuit, a second energizing meanscomprising a battery and signal means in series therewith, saidsecondnamed battery operating with the circuit to be tested in buckingor aiding arrangement,

means for throwing the second-named battery out of circuit withoutpermanently breaking the circuit, said second-named battery being of adifferent voltage from said first-named battery, and said signals havingdilierent normal operating voltages.

In testimony whereof, I have signed my name to this specification this6th day of December, 1930.

WILLIAM A. FROECKMAN.

